Johnk,
I am so MUCH in agreement with you here. There are a number of very old drivers that can be used in modern systems that are, in some respects, unmatched by anything new. Some of these are limited in application because of practical concerns (size) but not in terms of sound quality (e.g., Western Electric 555 driver and 15a horn combination for midrange). I own a "modern" system where I have replaced the midrange driver/horn with a Western Electric 713b driver and 120125 horn. The driver was probably made around 1939.
I have heard a terrific system built around a 13" Jensen fieldcoil driver used as a bass/midrange driver with a simple highpasss network feeding a dome tweeter for very high frequencies. This is also a terrific sounding system based primarily on ancient drivers.
When stereo became popular, for practical reasons, the entire focus on speaker design was to develop smaller systems. Efficiency was also sacrificed in the process because, near the same time, higher powered transistor amplification became practical and cheap. In many respects, sound quality has not really recovered since then.